Hata K, Suzuki J-I & Kachi N (2010). Fine-scale spatial distribution of seedling establishment of the invasive plant, Leucaena leucocephala, on an oceanic island after feral goat extermination. Weed Research50, 472–480.
On oceanic islands, native vegetation disturbed by feral goats has been invaded by an alien shrub, Leucaena leucocephala, after goat removal. We investigated how the distribution of L. leucocephala at the earliest stages of invasion was related to the distance from seed sources and the structure of the herbaceous vegetation. At a fine spatial scale in Nakoudojima Island, Japan, an oceanic island in the western Pacific, we calculated correlations between the presence of L. leucocephala and its distance from a forest dominated by L. leucocephala, the height of the herbaceous vegetation, and the depth of litter accumulation. The occurrences of L. leucocephala plants smaller than 1.3 m in height were negatively correlated with distance from L. leucocephala forest, the height of the herbaceous vegetation, and litter depth. On the other hand, the occurrence of plants larger than 1.3 m in height was correlated only with distance from L. leucocephala forest. Our results suggested that the distribution of smaller individuals of an alien plant at specific sites would be related not only to the distance from its seed sources, but also to the structure of the herbaceous vegetation.